Multicolumn selectivity inversion generator for production of high purity actinium for use in therapeutic nuclear medicine

A method f or producing a solution of actinium and optionally present radium daughter radionuclide ions that is substantially free of thorium parental ion impurities comprising the steps of:

• (a) contacting an aqueous parent-daughter radionuclide ion solution having a pH value of about 8 or less that contains sulfate ions as well as thorium parental radionuclide ions and actinium and optionally present radium desired daughter radionuclide ions with a first solid phase separation medium that provides a decontamination factor of about 102 or greater for the actinium and optionally present radium desired daughter ions from the thorium parent ion impurities under the conditions of contact, said separation medium comprising water-insoluble polymeric sulfonate group-containing cation-exchange resin particles, and maintaining that contact for a time period sufficient for said actinium and optionally present radium ions to be bound by the solid phase first separation medium to form desired daughter ion-laden separation medium and a thorium ion-containing, desired daughter-depleted parent-daughter solution;
• (b) separating the thorium ion-containing, desired daughter-depleted parent-daughter solution from the solid phase desired daughter ion-laden separation medium;
• (c) stripping the desired daughter radionuclide from the desired daughter-laden separation medium with an aqueous nitric or hydrochloric acid solution to form an aqueous nitric or hydrochloric acid solution of actinium and optionally present radium desired daughter radionuclide ions that may contain trace amounts of parental thorium ion impurities;
• (d) contacting said aqueous nitric or hydrochloric acid solution of actinium and optionally present radium desired daughter radionuclide ions that may contain trace amounts of parental thorium ion impurities of step (c) with a second solid phase separation medium that provides a decontamination factor of about 102 or greater for the actinium and optionally present radium desired daughter ions from the thorium parent ion impurities under the conditions of contact, and maintaining that contact for a time period sufficient for the parent thorium radionuclide that may be present to be bound by the second solid phase separation medium to form a solution of actinium and optionally present radium desired daughter radionuclide ions that is highly purified and is substantially free of thorium parental radionuclide ion impurities;
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• (e) separating the solid and solution phases to provide a solution of actinium and optionally present radium desired daughter radionuclide ions that is highly purified and is substantially free of thorium parental radionuclide ion impurities.

A method for producing a solution of daughter actinium radionuclide ions that is substantially free of thorium parental radionuclide ion impurities comprising the steps of:

• (a) contacting an aqueous acidic parent-daughter radionuclide ion that contains about 0.05 to about 4.0 M sulfate ions as well as thorium parental radionuclide ions and actinium and radium desired daughter radionuclide ions with a first solid phase separation medium that provides a decontamination factor of about 102 or greater for actinium and radium desired daughter ions from the thorium parent radionuclide ion impurities under the conditions of contact, said separation medium comprising water-insoluble polymeric sulfonate group-containing cation-exchange resin particles, and maintaining that contact for a time period sufficient for said actinium and radium ions to be bound by the solid phase first separation medium to form desired daughter ion-laden separation medium and a thorium ion-containing, desired daughter-depleted parent-daughter solution;
• (b) separating the desired daughter-depleted parent-daughter solution from the solid phase desired daughter ion-laden separation medium;
• (c) stripping the desired daughter radionuclide ions from the desired daughter-laden separation medium with an aqueous nitric acid solution whose nitric or hydrochloric acid concentration is about 0.5 to about 8 M or greater to form an aqueous nitric or hydrochloric acid solution of actinium and radium desired daughter radionuclide ions that may contain trace amounts of parental thorium ion impurities;
• (d) contacting said aqueous nitric or hydrochloric acid solution of actinium and optionally present radium desired daughter radionuclide ions that may contain trace amounts of parental thorium ion impurities of step (c) with a second solid phase separation medium that has a decontamination factor of about 102 or more for actinium desired daughter radionuclide ions from thorium parental ion impurities under the conditions of contact, said second solid phase separation medium comprising
• (a) dipentyl pentylphosphonate extractant coated on an inert solid support, (b) a mixture of trioctyl and tridecyl methyl ammonium chlorides or nitrates sorbed on an inert water-insoluble support, or an anionic-exchange resin, and maintaining that contact for a time period sufficient for the parent thorium radionuclide that may be present to be bound by the second solid phase separation medium to form a solution of actinium and radium desired daughter radionuclide ions that is highly purified and is substantially free of thorium parental radionuclide ion impurities;
• (e) separating the solid and solution phases to provide a solution of actinium and optionally present radium desired daughter radionuclide ions that is highly purified and is substantially free of thorium parental radionuclide ion impurities;
• (f) contacting said separated solution of step (e) with a third solid phase separation medium that that provides a decontamination factor of about 102 or greater for the actinium ions from radium ions under the conditions of contact, and maintaining that contact for a time period sufficient to form solid phase actinium-laden separation medium and a radium ion-containing, actinium-depleted solution;
• (g) separating the solid and liquid phases formed;
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• (h) stripping the actinium ions from said solid phase actinium-laden separation medium with dilute hydrochloric acid to form a solution of actinium ions in hydrochloric acid.